In the medical field, a discharge device is known which is used in order to discharge a drug solution to be applied to a lesion area inside biological organs (for example, a body cavity such as esophagus, airway, bowel, urinary duct, and other internal organs), in order to discharge a gel-phase substance to be applied in order to protect an inner wall of the biological organ during various treatments, and in order to discharge a cleaning solution for cleaning the biological organ, for example.
The discharge device is configured to guide a discharge substance to flow to a desired site inside a living body through an elongated flexible catheter (shaft). The catheter is formed to have a small outer diameter so that the catheter can be delivered to a relatively thin site in a biological lumen or the like. A discharge substance circulating lumen (flow path) formed inside the catheter is formed to have a small sectional area in accordance with the outer diameter of the catheter.
Incidentally, the discharge device is widely used in order to discharge various discharge substances inside the living body. One of various uses is to remove foreign substances present inside the biological organ. For example, the discharge device can be used in order to discharge a fluid such as a liquid and the like inside the biological organ. In this manner, various treatments for causing the fluid to wash the foreign substances away are performed so as to discharge foreign substances out from the living body or so as to move the foreign substances to a desired position inside the living body. In addition, removal target foreign substances include calculus fragments that are formed by fragmenting a urinary calculus when urolithiasis is treated (refer to JP-T-2001-512355).
As described above, since the catheter itself is formed to have a small diameter and thus has restrictions on a sectional area of the lumen included in the discharge device, the catheter cannot be designed larger. Therefore, it can be difficult to increase a discharge amount or a flow rate of the discharge substance that is discharged through the lumen of the catheter, thereby causing a problem in that the discharge amount or the flow rate required for removing the foreign substances may not be sufficiently obtained. In addition, when the discharge device is used for another use except for removing the foreign substances, for example, when a medicine is intended to be discharged, it can be difficult to secure a desired discharge amount. Consequently, there can occur a problem in that an effect of the medicine (medicinal effect) may not be sufficiently achieved.